Collapsible stretch frame and canvas



Feb. 10, 1970 PREHTL ETAL COLLAPSIBLE STRETCH FRAME AND CANVAS 2 Sheets-Sheet 1 Filed June 4, 1968 5 "mm W o A mmw y M nw Wu P. 0.

Wm M R6 w United States Patent Ofice 3,494,409 Patented Feb. 10, 1970 U.S. Cl. 160-3741 4 Claims ABSTRACT OF THE DISCLOSURE A prefabricated stretch frame for use by artists and painters and capable of being (I) quickly assembled and (2) likewise quickly dismantled without tools. Two side frame members have their outward lengthwise edges stapled to corresponding longitudinal flaps on the reverse side of the canvas and provide a basic three-part coilable unit. A pair of transverse end frame members spread the side frame members and canvas and have mitered ends separably united with coacting mitered ends of the side members. The respective transverse ends of the canvas provide tautening and attaching flaps. These flaps are drawn and stretched over the end frame members and are detachably fastened in place.

This invention relates to a portable prefabricated knockdown stretch frame and complemental canvas which is expressly designed and novelly adapted for use in the field of art and painting and has to do with a sectional stretch frame which is compact and convenient, is easy to assemble and disassemble, saves time and labor, can be purchased and carried in a reusable mailing tube, is virtually wrinkle-proof when the canvas is properly mounted and well serves the many purposes for which it has been ingeniously planned and advantageously used.

Artists and painters are conversant with the fact that it is difficult and often impractical to remove a canvas from its complemental frame without running the risk of damaging the picture, the canvas, or 'both. Experience has shown that currently available framed canvases usually take at least an hour, require tools and, at best present a perplexing task. These and other difliculties have posed a problem. Accordingly, a principal object in the instant matter is to effectually cope with and satisfactorily solve the over-all problem. To the ends desired, easy assembling results from the use of a properly cut canvas and knockdown stretch frame, and keeping in mind that the structure comes partly assembled, saves the painter valuable time and makes for a tighter, tauter and wrinklefree canvas for effective results. Then, too, with the construction shown, if an artist in one locality wishes to exhibit a given painting in another locality, all that he has to do is disassemble his frame and painting, put the same in a mailable tube, mail it to the desired destination and, in minutes after it arrives, the recipient can set it up for display with little or no trouble.

Briefly the invention is characterized by a piece of canvas which in and 'of itself is comparable with ordinary canvases used for paintings. Then, too, the canvas is mounted, as usual, on a frame. However, and in the instant situation the frame is uniquely constructed and the edge portions of the canvas are provided with flaps which are connected in an original manner with the coacting outer marginal edge portions of the four frame members or rails. In carrying out the principles of the present invention the side frame members are slightly longer than the cooperating transverse end frame members. These side frame members have longitudinally rabbeted surfaces which are laid or placed fiatwise atop the reverse edge portions of the canvas. The flaps which project beyond the outer edges of these frame members are lateral to the canvas proper and are stapled to the outer edge portions of the respective side frame members. All four of the frame members are generally rectangular in crosssection and are alike in construction. The respective outer ends of the frame members are conformably mitered. This is to say, the mitered ends of the transverse frame members abut the coacting mitered ends of the side frame members and the abutting surface portions are provided with cooperating kerfs which define suitable mortises for reception of insertable and removable corner assembling wedges. The outer marginal edges of the transverse frame members are provided with channel-like grooves into which coacting portions of the folded free edges of the canvas are seated and held in place by forcibly pressed retaining keys. These keys may be in the form of short dowel pins or T-shaped members as desired.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is a view in perspective of the canvas placed flatwise on a support surface with the obverse side down and the reverse side up and with the permanently stapled or attached side rails or frame members in coplanar spaced apart parallel relationship.

'FIG. 2 is a view also in perspective and based on FIG. 1 and wherein one transverse frame member has been positioned between the coacting side frame members and the other one is shown in a position ready for use.

FIG. 3 is an enlarged fragmentary perspective view showing a corner portion, the purpose of which is to bring out the mortises and one of the wedges which is partially inserted into the aligned mortises.

FIG. 4 is a fragmentary perspective view which shows the step wherein the device has been inverted with the obverse side facing up and with one free tautening flap firmly pushed over and pressed and held down with the fingers in readiness to be keyed or anchored in place.

FIG. 5 is an enlarged fragmentary perspective view of a corner portion and which follows the step shown in FIG. 4 and wherein the vertical upstanding frame is so located that the user can conveniently plug the anchoring pins in the attachable and detachable canvas flap.

FIG. -6 is a plan or edge elevational view showing the flap of FIG. 5 completely secured in place.

FIG. 7 is a view in perspective showing a T-shaped retainer which may be used instead of the dowel pin type shown in FIGS. 5 and 6.

FIG. 8 is a view in perspective with the canvas omitted and showing all four of the frame members and all four of the insertable and removable wedges.

FIG. 9 is a view on a smaller scale observing the reverse side and with the frame members completely assembled and with the upper left hand corner portion broken away and appearing in section.

FIG. 10 is a sectional view taken on the plane of the section line 10-10 of FIG. 9.

FIG. 11 is a cross-section taken on the plane of the section line 1111 of FIG. 9 and FIG. 12 is a view in perspective showing the receptacle part of a mailing tube and also showing the component parts of the overall device collapsed and positioned in the tube for storage, handling or mailing as the case may be and wherein certain component parts, such as the wedges and dowel pins, are not shown.

The aforementioned canvas is denoted by the numeral 14 and is here illustrated as of suitable size and as being substantially rectangular in plan, that is the body portion thereof. The longitudinal marginal edges of the canvas are bent or folded up as at 16 to define flaps 18. These flaps 18 coordinate with transverse end flaps 20 which will be hereinafter set forth. The rectangular stretch frame is of a portable knockdown construction and the over-all device including the canvas and frame is collapsible to accomplish the step-by-step results shown in FIGS. 1 to 6 and also the storage and mailing result shown for example in FIG. 12. Referring now to FIG. 1 it will be evident that the longitudinal side rails or frame members are denoted at 22 and they are substantially rectangular in cross-section and are of a length less than the over-all length of the canvas. As shown in FIG. 8 the outer marginal edge 24 is substantially flat. One surface portion is rabbeted from end to end as denoted at 26 to define the minimal canvas contacting rib or surface 28. The respective ends are mitered as denoted at 30 and the end portions are provided with kerfs which are hereinafter referred to more specifically as mortises 32. As shown in FIG. 1 the rabbeted surfaces 26 are placed upon the reverse surface portion of the canvas and the flap 18 is carefully drawn up and is secured to the surface 24 by permanent staples 34. Summarizing the aspect of the concept evident from FIG. 1 it will be seen that a principal unit of the over-all device comprises the canvas 14 having marignal flaps 18 stapled to outer marginal edge portions 24 of the cooperating longitudinal side rails or frame members 22. It will be further noted that the mitered ends 30 terminate inwardly of the projecting manually foldable holddown flaps 20.

With reference now to FIG. 2 which is similar in position and purpose to FIG. 1 it will be evident that the transverse rails or frame members which go to complete the over-all rectangular stretch frame are shorter and alike in construction and each is denoted by the numeral 36. Here again the underneath surface of each rail or member is rabbeted as at 38 to provide a minimal straining rib 40 and to provide the desired clearance already mentioned. The mitered ends of these two rails 36 are interposed between the mitered end portions of the longitudinal rails 22. One end rail is shown in position at the right in FIG. 2 and the other rail at the left is about to be put into position in what is believed to be a self-evident manner. At this point it can be assumed that with the two rails 36 in place as shown in FIGS. 9, 10 and 11 for example the mortises at the corner portions are lined up to accommodatingly receive the insertable and removable frame assembling and retaining wedges. Each wedge is the same in construction and one wedge is denoted by the numeral 42 and as shown in FIG. 3 it is partly slid into the mortises provided and has gripping flanges 44 to assist in applying and removing the wedge. The wedges can be applied at this stage of the assemblage or they can be applied later that is after the end flaps 20 of the canvas have been secured in place and to in this manner assist (not shown) in straining and tightening the canvas. It can be assumed now that after the first three steps have been carried out in FIGS. 1 to 3 the canvas is turned up so that the obverse side faces upwardly as shown in FIG. 4 after which one of the flaps 20 can be folded down. This necessitates tucking in a corner portion as denoted at 46. Now the fiap is forcibly pressed over and down against the cooperating outer marginal surface of the end or transverse frame member. This step can be best accomplished by placing the device on an end and in an upright position as shown in FIG. after which the flap 20 can be tautened and forced as at 48 into the groove 50 which is provided therefor in the rail surface 52. At this time the readily applicable and unmovable anchoring plugs or dowel pins 54 can be pressed into place. Instead of using dowel pins as shown in FIGS. 5 and 6 it would be within the purview of the concept to substitute and use the T-shaped retainers, that is of the type denoted at 56 in FIG. 7.

It is submitted that the canvas and frame components are clearly shown in the views of the drawings and that the preferred steps of assembling are brought out in FIGS. 1 to 5 with particularity. The make-up of the four-part expansible frame is shown in FIG. 8 with the parts exploded and also with the required number of insertable and removable wedgesx. The completed construction is shown to advantage; it is submitted in FIGS. 9, 10 and 11. Then, in FIG. 12 one can appreciate that taking thedevice of FIG. 1 it is possible to roll the half portions together to provide a small and compact package which can be inserted into a body portion 58 of a mailing tube as shown in FIG. 12. The cap of the mailing tube is shown at 60'. FIG. 12 also shows how the detachable and applicable transverse rails can be inserted and placed compactly within the confines of the tube 58. As already mentioned it was thought to be unnecessary in FIG. 12 to attempt to show the detachedwedges 42 and retaining elements or members 54 and 5'6. In fact, these component parts can be placed in a separate envelope (not shown) at the time of packaging for .sale. They can also be handled in whatever manner desired when the tube is completed and readied for mailing.

With referenc again to FIGS. 10 and 11 it will be seen that the rabbeted surfaces of the rails or members provide clearance so that the canvas is stretched over the ribs 28 for best results.

It is submitted. that a clear comprehension of the subject matter of the invention and the manner of constructing and assembling the component parts will doubtless be clear from the views of the drawing taken in conjunction with the detailed description. Accordingly, a more extended description is deemed to be unnecessary.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be restorted' to, falling within the scope of the in vention.

What is claimed as new is as follows:

1. In a collapsible stretch frame, a canvas, a knockdown stretch frame embodying a first pair of longitudinal side frame members having longitudinally rabbeted surfaces residing flatwise atop coacting everse surface portions of said canvas, the respectively adjacent marginal edge portions of said canvas projecting beyond predetermined outward marginal edges of said side frame members and being fashioned into lateral flaps, said flaps overlapping and being permanently attached to the marginal edges of said side frame members, the respective ends of said frame members being mitered and mortised and terminating in positions spaced inwardly from the respectively adjacent free transverse marginal end portions of said canvas, a pair of transverse end frame members complemental to said side frame members and spanning the space between the cooperable mitered ends of said side frame members and having mortised, mitered and mated ends movably abutting the cooperable mitered ends of said side frame members, said transverse end frame members also having longitudinally rabbeted surfaces residing atop portions of the reverse surface of said canvas, the respective transverse end portions of said canvas projecting beyond the outward lengthwise edges of said transverse end frame members and providing stretching and holddown flaps, said outward lengthwise edges being provided with longitudinal grooves, said holddown flaps being tautly stretched over said lengthwise edges and bridging said grooves, flap retaining members removably lodged in said grooves and serving to retentively nest and anchor said holddown flaps in their respective grooves, and, in combination, a plurality of readily applicable and removable assembling and spreading wedges fitted removably in the coacting mortised end portions of the side members and transverse end frame members respectively.

2. The collapsible stretch frame and canvas defined in and according to claim 1 and wherein said wedges have inward accessible ends provided with limit stop and gripping flanges, said wedges being adapted to be partly inserted to maintain the aforementioned frame members temporarily in frame forming relationship and after the over-all canvas has been initially stretched lengthwise and crosswise, said wedges being adapted to be driven home in their respective mortises in a manner to expand all four corners of the frame and to render the stretched canvas as taut and wrinkle-proof as desired, said wedges being readily removable with the aid of the aforementioned gripping flanges.

3. The stretch frame defined in and according to claim 2 and wherein said flap retaining members comprise a plurality of force-fitted dowel pins which are plugged in a predetermined manner in their respectively cooperable grooves, said dowel pins being frictionally but removably retained in their given positions.

4. The stretch frame and canvas defined in and according to claim 2 and wherein said flap retaining members comprise a plurality of force-fitted T-shaped retainers which are plugged in place in their respectively cooperable grooves and are frictionally but removably retained therein.

References Cited UNITED STATES PATENTS 1,128,362 2/1915 Rawbon 160374.1 1,916,022 6/1933 Shull 160-3741 1,964,332 6/1934 Rembaum 160372 X 2,042,726 6/1936 Mueller l394 X 2,834,412 5/1958 Velke 395 2,907,362 10/195 Owen.

3,133,375 5/1964 Myren 160374.1 3,137,088 6/1964 Spertus 160-378 3,238,996 3/1966 Munn 160374.1

DAVID J. WILLIAMOWSKY, Primary Examiner P. C. KANNAN, Assistant Examiner US. Cl. X.R. 

